1. Field of the Invention
The present invention relates generally to motorcycles. More particularly, the present invention relates to turn signal and directional light control systems for motorcycles. Even more particularly, the present invention relates to a circuit configuration designed to control certain aspects of the operation and functioning of directional signals on a motorcycle.
2. Description of Related Areas of Art
Automatically cancelling the turn signals on a motorcycle is considerably different from doing so on an automobile. An automobile's turn signals are typically turned off by rotation of the steering wheel. However, at speeds above approximately 15 mph, the motion of the handlebars on a motorcycle is nearly imperceptible, making steering cancellation a poor method.
Some motorcycle manufacturers cancel the signal after a single, preset distance or time. Oversimplification like this is not desirable because it does not accommodate differing situations. Still other systems have elaborate mechanical and electromechanical systems designed to detect changes in the motorcycle's vertical alignment, or gravitational and/or inertial effects. Such systems are typically complex, unreliable and cumbersome.
The prior art is replete with systems utilizing various physical response mechanisms to switch off turn signals after a turn has been completed. A wide variety of such electromechanical systems has been developed. Mercury switches are used in U.S. Pat. No. 3,876,976 issued to Cross, Jr. on Apr. 8, 1975 entitled "Tilt Actuated Directional Signal For Vehicles". Gravitational and inertial forces experienced by the vehicle due to inclination from its normally upright position or due to alteration in its direction of motion cause mercury switches to turn off turn signals. Similarly, a mercury switch is used in U.S. Pat. No. 3,931,529 issued to Williamson, Jr. on Jan. 6, 1976 and entitled "Turn Signal Indicator". The system disclosed in U.S. Pat. No. 4,363,022 issued to Manacci on Dec. 7, 1982 entitled "Self-Cancelling Motorcycle Turn Signal Which Recognizes Balance" also uses mercury switches adjusted to open when a motorcycle is returned to an upright position after tilting due to a turn.
In U.S. Pat. No. 4,030,066 issued to White on June 14, 1977 and entitled "Automatic Cancellation Means For Vehicle Turn Indicator Signals", the turn signals are turned off on completion of a turn by means of a gyroscope mounted on the vehicle and utilizing the precession movement of the gyroscope resulting from turning of the vehicle to actuate a signal cancelling means.
Two other patents utilize mechanical linking systems to turn off signals on a motorcycle. U.S. Pat. No. 4,125,827 issued to Roudebush, Jr. on Nov. 14, 1978 entitled "Automatically Cancelling Turn Signal" turns off the turn signal upon upshifting of a motorcycle into a higher gear. Mechanical linkage responsive to a weight shift in the motorcycle in a turn is used to turn off the signals in U.S. Pat. No. 4,398,175 issued on Aug. 9, 1983 to Gamba entitled "Apparatus For Automatically Cancelling A Turn Signal".
The present invention incorporates a "burned out bulb detector" in addition to the signal canceller. In earlier devices developed to address this situation, electromechanical devices have been used to change operation of the turn signals in order to comply with legal and common sense safety standards and practices. For example, bimetallic springs, which physically behave differently when the lamp bulb is burned out, have been used along with a device having contacts attached through the spring.
A turn signal control system circuit which overcomes the shortcomings, limitations and restrictions of prior devices would be a significant advancement in the art.